The present invention relates to combustion equipment and more particularly to an improved diffuser for a gas duct burner.
In order to increase combustion in a duct burner downstream of a gas turbine, it is desirable to increase the mixing rate of the fuel and turbine exhaust gas (TEG) in order to stabilize the flame and create a low velocity zone. Enhanced combustion results in a decrease in the amount of carbon monoxide generation. Techniques have been utilized for improving combustion and lowering carbon monoxide generation through the use of stabilizers and diffusers. Stabilizers entrain fuel within an ignition zone, and diffusers create an obstruction in the flow stream to create a wake flow. However, enhanced downstream mixing rates and lower carbon monoxide generation is not sufficiently achieved by present designs.
A need has thus arisen for an improved diffuser for the generation of smaller and out of plane vortices to enhance the downstream mixing of fuel and TEG which also reduces carbon monoxide generation.
In accordance with the present invention, a diffuser for a gas duct burner having a fuel pipe and a plurality of stabilizers is provided. The diffuser includes a plate having first and second spaced apart ends defining a length, and first and second spaced apart sides defining a width. The plate has a first portion having a uniform width which is disposed adjacent to a stabilizer and a second portion having a variable width.